An improved depiction of precipitation in complex terrain can be gained by fusing observations from multiple platforms together in a precipitation estimation system such as the one developed at the University of North Dakota. This system utilizes surface observations, radar, and, to a minor extent, geostationary satellite data streams in a manner to optimize the strengths of each data stream while mitigating their weaknesses. The complex terrain issues noted above require different approaches to the blending algorithms developed for simpler terrain environments.
Over the past year we have implemented methods to allow applications of the UND Pavement Precipitation Accumulation Estimation System (PPAES) within complex terrain, including new rule sets introduced for dealing with radar beam blockage and radar ray propagation as well as utilization of Rapid Refresh fields in areas where radar coverage is not available, which is particularly problematic in the Intermountain West and Alaska. Tests of our methodology will be conducted for selected case studies over a domain covering the state of Utah and adjacent areas of neighboring states. We also plan to perform a separate case study to demonstrate the benefits of full utilization of Clarus data within PPAES.